Release notes

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New TTS model: supertonic_api_3

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What’s new

1. supertonic_api_3 — Successor to supertonic_api_1
   • Inherits the ultra-low latency profile of supertonic_api_1
   • Significantly improved speech stability — far fewer pronunciation and reading errors
   • Trained differently from the open-weights Supertonic 3 release, so this is a distinct model
   • Supports 31 languages: en, ko, ja, ar, bg, cs, da, de, el, es, et, fi, fr, hi, hr, hu, id, it, lt, lv, nl, pl, pt, ro, ru, sk, sl, sv, tr, uk, vi
   • Voice settings: speed only (same as supertonic_api_1)
2. supertonic_api_1 is now the legacy supertonic model
   • Still available for existing integrations
   • New projects should use supertonic_api_3
3. Model selection expanded — TTS requests now accept sona_speech_2, sona_speech_2_flash, supertonic_api_3, supertonic_api_1, and sona_speech_1.

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New TTS models: sona_speech_2, sona_speech_2_flash, and supertonic_api_1

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What’s new

1. sona_speech_2 — Multilingual flagship
   • Supports 23 languages
   • Improved speech quality and stability
   • Supports include_phonemes and normalized_text
   • Voice settings: all parameters except subharmonic_amplitude_control
2. sona_speech_2_flash — Low-latency variant
   • Same 23 languages as sona_speech_2
   • Optimized for lower latency
   • Voice settings: pitch_shift, pitch_variance, speed, duration
3. supertonic_api_1 (beta) — Lightweight low-latency model
   • Supports en, ko, ja, es, pt
   • Designed for fastest inference and simplest setup
   • Voice settings: speed only
4. Model selection expanded — TTS requests now accept sona_speech_2, sona_speech_2_flash, supertonic_api_1, and sona_speech_1.

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Custom voices and streaming TTS (beta)

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What’s new

1. Preset vs custom voice separation
   • Preset voices are designed and provided by Supertone.
   • Custom voices are clones registered and managed by the customer.
   • New endpoints under /v1/custom-voices/... for managing customer-owned voices.
2. Voice cloning via the API
   • Voice cloning, previously only available in Supertone Play, is now supported via API.
   • See Create cloned voice.
3. Streaming TTS (beta)
   • A beta version of the streaming TTS API is available, ideal for real-time applications such as AI chatbots and character-based chat.
   • See Stream speech.

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Supertone API grand open

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Major changes

1. Voice ID structure redesign
   • Changed from {character-language-style} combination → unified to character-based voice_id.
   • language and style parameters moved into the request body for flexible calling.
2. New TTS model
   • Replaced pro and turbo → unified into a single sona_speech_1 model.
   • Improved speech quality; text length limit increased from 200 to 300 characters.
3. Cloned voice API support
   • Cloned voices created in Play can now be called via the API.
   • Automatic integration within the same account, with permission-based security.
4. Play and pricing integration
   • API usage applies Play’s credit system directly.
   • Shared credits and unified billing — no separate pricing plans.
5. Enhanced voice search
   • Filtering and exploration via GET /voices and GET /voices/search.
   • Each voice exposes supported languages, styles, and samples.
6. Predict Duration API
   • Estimate speech length before generation — no credits deducted.
7. New user guide and documentation
   • Practical documentation including Quickstart, Voice Selection, Error Handling, and FAQ.
   • Complete documentation renewal focused on the Play ↔ API integration flow.

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Voice search update

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What’s new

• New endpoint for searching voices with filters and keywords.
• Filter by language, gender, age, and use case.
• Keyword search across voice names and descriptions.
• Page-based pagination for large result sets.

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Supertone API closed beta launch

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Key features

1. Text-to-speech voice synthesis service.
2. Voice list inquiry and usage check APIs.

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Endpoints

• List voices — retrieve available voices.
• Create speech — convert text to speech.
• Get voice usage — check API usage.

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Getting started

1. Sign up at console.supertoneapi.com.
2. Apply for closed beta participation.
3. Issue an API key from the console.
4. Integrate and use the API.

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Console features

• API key issuance and management.
• Minute-based API usage monitoring.